| 8"/55 caliber naval gun | |
|---|---|
 New Orleans B turret following a Japanese torpedo-initiated explosion of the forward magazine during the Battle of Tassafaronga. | |
| Type | Naval gun |
| Service history | |
| In service | 1925–1975 |
| Used by | United States |
| Wars |
World War II Korean War Vietnam War |
| Production history | |
| Variants | Mk 9, Mk 12, Mk 14, Mk 15, Mk 16 |
| Specifications | |
| Barrel length | 440 inches (11 m) bore (55 calibers) |
|
| |
| Shell | 260 pounds (118 kg)[2] H.E. |
| Caliber | 8 inches (20 cm) |
| Muzzle velocity | 2,500 feet per second (760 m/s)[1] |
| Maximum firing range | 30,050 yards (27,480 m)[1] |
The 8"/55 caliber gun (spoken "eight-inch-fifty-five-caliber") formed the main battery of United States Navy heavy cruisers and two early aircraft carriers. United States naval gun terminology indicates the gun fired a projectile 8 inches (203 mm) in diameter, and the barrel was 55 calibers long (barrel length is 8 inch × 55 = 440 inches or 11 meters).[3]
,_USS_Pensacola_(CA-24)_and_USS_New_Orleans_(CA-32)_at_Pearl_Harbor_on_31_October_1943.jpg){kind=link}
Compare the rounded roofs of early Mark 9 twin and triple turrets of Salt Lake City and Pensacola with the later turrets of New Orleans on the right.
Mark 9[]
These built-up guns weighed about 30 tons including a liner, tube, jacket, and five hoops. A down-swing Welin breech block was closed by compressed air from the gas ejector system. Loading with two silk bags each containing 45-pounds (20 kg) of smokeless powder gave a 260-pound (120 kg) projectile a velocity of 2800 feet per second (850 m/s).[1] Range was 31,860 yd (29,130 m) at the maximum elevation of 41 degrees.[1][4]
Mark 12[]
These simplified built-up guns eliminated hoops to reduce weight to 17 tons. The breech mechanism was similar and loading two silk bags each containing 43-pounds (20 kg) of smokeless powder gave a 335-pound (152 kg) projectile a velocity of 2500 feet per second (760 m/s).[1] Each gun could fire about four rounds per minute. Maximum range was 30,050 yd (27,480 m) at the maximum elevation of 41 degrees.[5]
Mark 14[]
These guns were similar to Mark 9, with the same shell weight and maximum range,[4] with a smaller chamber and rifling twist increased from 1 in 35 to 1 in 25 in a chromium-plated bore.
Mark 15[]
These guns were similar to Mark 12, with the same shell weight and maximum range, with the smaller chamber of the Mark 14 gun.[5] Useful life expectancy was 715 effective full charges (EFC) per liner.
Mark 16[]
These self-loading guns with lined monobloc construction and vertical sliding breech blocks weighed about 20 tons. Semi-fixed ammunition (projectile and powder case handled separately) with 78 pounds (35 kg) of smokeless powder gave a 335-pound (152 kg) projectile a velocity of 2500 feet per second (760 m/s).[1] Each gun could fire about ten rounds per minute. Useful life expectancy was 780 EFC per liner. Range was 17 miles (27 kilometers) at the maximum elevation of 41 degrees.[1][6] This gun was modified for the experimental Major Caliber Lightweight Gun.
Ships mounting 8"/55 caliber guns[]
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_off_Hungnam_December_1950.jpg){kind=link}
The heavy cruiser USS Saint Paul (CA-73) fires her 8"/55 caliber Mark 15 guns at Chinese troops threatening the evacuation of United Nations troops from Hungnam, North Korea, in December 1950 during the Korean War.
| Ship | Gun Installation[1] |
|---|---|
| USS Lexington (CV-2) | Mk 9 guns in four 190-ton twin turrets |
| USS Saratoga (CV-3) | Mk 9 guns in four 190-ton twin turrets |
| USS Pensacola (CA-24) | Mk 9 (later Mk 14) guns in two 190-ton twin turrets and two 250-ton triple turrets |
| USS Salt Lake City (CA-25) | Mk 9 (later Mk 14) guns in two 190-ton twin turrets and two 250-ton triple turrets |
| USS Northampton (CA-26) | Mk 9 (later Mk 14) guns in three 250-ton triple turrets |
| USS Chester (CA-27) | Mk 9 (later Mk 14) guns in three 250-ton triple turrets |
| USS Louisville (CA-28) | Mk 9 (later Mk 14) guns in three 250-ton triple turrets |
| USS Chicago (CA-29) | Mk 9 guns in three 250-ton triple turrets |
| USS Houston (CA-30) | Mk 9 guns in three 250-ton triple turrets |
| USS Augusta (CA-31) | Mk 9 (later Mk 14) guns in three 250-ton triple turrets |
| USS New Orleans (CA-32) | Mk 9 (later Mk 14) guns in three 294-ton triple turrets |
| USS Portland (CA-33) | Mk 9 (later Mk 14) guns in three 250-ton triple turrets |
| USS Astoria (CA-34) | Mk 9 guns in three 294-ton triple turrets |
| USS Indianapolis (CA-35) | Mk 9 (later Mk 14) guns in three 250-ton triple turrets |
| USS Minneapolis (CA-36) | Mk 9 (later Mk 15) guns in three 294-ton triple turrets |
| USS Tuscaloosa (CA-37) | Mk 12 guns in three 250-ton triple turrets |
| USS San Francisco (CA-38) | Mk 12 guns in three 250-ton triple turrets |
| USS Quincy (CA-39) | Mk 12 guns in three 250-ton triple turrets |
| USS Vincennes (CA-44) | Mk 12 guns in three 250-ton triple turrets |
| USS Wichita (CA-45) | Mk 12 guns in three 314-ton triple turrets |
| USS Baltimore (CA-68) | Mk 12 guns in three 300-ton triple turrets |
| USS Boston (CA-69) | Mk 15 guns in three 300-ton triple turrets |
| USS Canberra (CA-70) | Mk 15 guns in three 300-ton triple turrets |
| USS Quincy (CA-71) | Mk 15 guns in three 300-ton triple turrets |
| USS Pittsburgh (CA-72) | Mk 15 guns in three 300-ton triple turrets |
| USS Saint Paul (CA-73) | Mk 15 guns in three 300-ton triple turrets |
| USS Columbus (CA-74) | Mk 15 guns in three 300-ton triple turrets |
| USS Helena (CA-75) | Mk 15 guns in three 300-ton triple turrets |
| USS Oregon City (CA-122) | Mk 15 guns in three 300-ton triple turrets |
| USS Albany (CA-123) | Mk 15 guns in three 300-ton triple turrets |
| USS Rochester (CA-124) | Mk 15 guns in three 300-ton triple turrets |
| USS Bremerton (CA-130) | Mk 15 guns in three 300-ton triple turrets |
| USS Fall River (CA-131) | Mk 15 guns in three 300-ton triple turrets |
| USS Macon (CA-132) | Mk 15 guns in three 300-ton triple turrets |
| USS Toledo (CA-133) | Mk 15 guns in three 300-ton triple turrets |
| USS Des Moines (CA-134) | Mk 16 guns in three 450-ton triple turrets |
| USS Los Angeles (CA-135) | Mk 15 guns in three 300-ton triple turrets |
| USS Chicago (CA-136) | Mk 15 guns in three 300-ton triple turrets |
| USS Salem (CA-139) | Mk 16 guns in three 450-ton triple turrets |
| USS Newport News (CA-148) | Mk 16 guns in three 450-ton triple turrets |
| USS Hull (DD-945) | Mk 16 gun in one 86-ton single automatic turret (8"/55 caliber Mark 71 gun installation) |
Weapons of comparable role, performance and era[]
- 203mm/50 Modèle 1924 gun French equivalent
- 20.3 cm SK C/34 Naval gun German equivalent
- 203 mm /53 Italian naval gun Italian equivalent
- 20 cm/50 3rd Year Type naval gun Japanese equivalent
- BL 8 inch Mk VIII naval gun UK equivalent
- 8"/55 caliber Mark 71 gun
References[]
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Campbell 1985 pp.127-131
- ↑ http://www.hnsa.org/doc/ordnance/pg056.htm
- ↑ Fairfield 1921 p.156
- ↑ 4.0 4.1 DiGiulian, Tony (27 April 2011). "United States of America 8"/55 (20.3 cm) Marks 9, 10, 11, 13 and 14". Navweaps.com. Archived from the original on 30 June 2011. http://web.archive.org/web/20110630230153/http://navweaps.com/Weapons/WNUS_8-55_mk9.htm. Retrieved 2011 07 21.
- ↑ 5.0 5.1 DiGiulian, Tony (7 February 2008). "United States of America 8"/55 (20.3 cm) Marks 12 and 15". Navweaps.com. Archived from the original on 30 June 2011. http://web.archive.org/web/20110630230055/http://navweaps.com/Weapons/WNUS_8-55_mk12-15.htm. Retrieved 2011 07 21.
- ↑ "New Cruiser Packs 8 inch Automatics" , May 1949, Popular Science detailed illustrations of Mark 16
- Campbell, John (1985). Naval Weapons of World War Two. Naval Institute Press. ISBN 0-87021-459-4.
- Fairfield, A.P. (1921). Naval Ordnance. The Lord Baltimore Press.
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